Process for producing filaments, threads, fibers, bands, films, and the like from proteins

ABSTRACT

Filaments, threads, fibres, bands, films, and the like are obtained by extruding a solution of a protein in an alkali into a coagulating bath and hardening the products by means of formaldehyde or other hardening agent capable of reacting with the amino groups of the protein, and also hardening the products by means of one or more formates of polyvalent metals in solution with or without one or more formates of univalent metals or other salts or organic compounds. Hardening may be effected in a single bath containing formaldehyde, sodium formate and aluminium triformate.  The polyvalent metal salt may be present as a complex salt.  If desired, a coagulating bath containing a formate may be used and the filaments or other products may be passed, without washing, from this bath to a hardening bath containing a polyvalent metal salt, the coagulating liquid adhering to the products being used as a constituent of the hardening bath.  A coagulating bath containing a salt of a polyvalent metal may be used and the unwashed products may be passed into a hardening bath containing a formate.  In forming the protein solutions some of the alkali is absorbed by or combines with the protein molecules and the amount of free alkali in the solution is reduced.  The amount of alkali used may be such that there is not more than 0.4 mols of free alkali per kg. of protein in the solution or it may be so small that there is no free alkali in the solution. Specification 577,526 is referred to.

Patented July l8, 1944 2,354,017 FlCE PROCESS FOR PRODUCING FILAMENTS, THREADS, FIBERS, BANDS, FILMS, AND THE LIKE FROM PROTEINS Lamhertus Alexander van Bergen, Aarle-Rlxtel,

Netherlands; vested in the Alien Property Custodian No Drawing. Application May 11, 1940, Serial No. 334,656. In the Netherlands May 11, 1939 6. Claims.

The role of the carboxylic groups also present in the protein complex and to which the property of binding metal ions is attributed, whereby the hydration or solubility should be influenced, is not completely clear. Therefore it is comprehensible that attempts have been made to improve the I properties of the protein products as to durability and water-resistance by neutralisation of. these groups. For this purpose salts of bivalent and polyvalent metals, e. g. salts of barium and .calcium, were added to the protein. Also aluminum sulphate and alums were used.

In applying these salts attention has mainly been paid to the positive ion and little or no attention to the negative ion. According to my invention it has appeared that the formate ion exercises a very specific action, particularly aluminium formate', alone or in combination with other formates. For instance conditions being otherwise equal casein fibers hardened at 30 C. during 6 hours in a bath containing 2% methanal, 10% sulphate of sodium and 5% sulphate of aluminium, will not be hardened to such a degree that they are resistant to boiling in water, whereas fibers hardened in a bath containing 2% methanal, Iormate of sodium and 6.3% ofaluminium triformate containing water of crystallization show even after only 1 hour a'good resistance to boiling though both baths contain an equal amount of aluminium.

Thespeciflc action oi this formate is not in the least clear, partlcularlywhen realizing that it is also possible that the eflect stated has to be attributed to the occurrence oi complex compounds, e. g. aluminium triformate the possibility of which occurrence can be supposed in all solutions in which the formate ion is present together with the aluminium ion, regardless of whether or not other positive and/or negative ions are also present.

I have further found that-the composition of the baths can differ very substantially and that the hardening agents may act separately or that their action can take place stepwise. possible to use other salts together with the formates or to form the formates in the baths. There have to be present, however, one or more positive ions of polyvalent metals, preferably aluminium, if desired together. with thoseoi univalent metals, and as the negative ion the formate, if desired together with other ions or even organic substances.

I have also found thathardening baths accord-. ing to the invention can be obtained by using formate-containing coagulating baths and bringing the products extruded therein into the formate-containing hardening baths without washing. It is also within the scope of my invention to bring the products from coagulating baths containing salts of polyvalent metals immediately 1. e. without washing into iormate-contalning hardening baths.

U. S. application Serial No. 314,880 discloses that in determining the alkali content of a solution of protein in 'alkali, it has to be taken into account that a part of the alkali used for dissolving the protein .is bound by the protein so that only the free alkali present in-the solution determines the alkalinity of the solution.

I have now found further also that the use of iormates in the hardening of fibers, threads, films and the like produced from solutions of protein in alkali, is important for the strength of these sponds to approximately It is also 4 products, particularly the strength in wet -condition, when they are obtained by extrusion of protein solutions having such an alkali content that at most 0.4 mol of free alkali per kg. protein is present, or even such an alkali content that there is a deficiency of alkali bound by the protein.

The significance of this influence of the hardening in the presence of fnrmates is clearly shown by/the following table, which relates to a casein solution of 16%, so that 0.2% free NaOH corre- 0.3 mol free NaOH per kg. of protein.

Per cent free N aOH- Strength in wet condition calculated per deniers in case of Sulphate hardening Formate hardening 32 Various changes may be made in the details dlsclosed in the foregoing specification without dehigh resistance to boiling which comprises extrudparting from the invention or sacrificing the advantages thereof.

I claim: I

1. A process for the production or filaments, threads, fibers, bands, illms and the like having a highresistance to boiling which comprises excoagulating bath, and hardening the resultant product by treatment with at least one aldehyde, and with a solution containing as essential ingredients at least one substance in dissolved condition selected from the group consisting of the iormates of polyvalent metals, and at least one substance in dissolved condition selected from the group consisting of the rormat'es of univalent metals, said protein solution containing at most 0.4 mol of free alkali per kg. of protein.

ing a solution of a protein in alkali into a coagulating bath, and hardening the resultant product by treatment with at least one aldehyde. and with a solution containing as essential ingredients at least one formate ion-yielding salt in dissolved condition, and at least one additional polyvalent metal ion-yielding salt in dissolved condition, said protein solution containing at most 0.4 mol of free alkali per kg. of protein.

'4. A solution for use in hardening the products obtained by extruding. a solution or a protein in alkali into a coagulating bath, said hardening solutioncontaining as essential ingredients at 1 ast one formate of a polyvalent metal and at least one formats of a univalent metal.

5. A solution for use in hardening the products obtained by extruding a solution of a protein in alkali into a coagulating bath, said hardening solution containing as essential ingredients methanal, sodium iormate and aluminum triiormate.

6. A solution for use in hardening the products obtained by extruding a solution of a protein in alkali into a coagulating bath, said hardening solution containing as essential ingredients 2% methanal, 10% sodium formate and 6.3% aluminum triformate.

r 3. A process for the production of filaments.

' threads, fibers, bands, iilms and the like having a LAMBERI'UB ALEXANDER VAN BERGEN. 

